Datacenter Sites in Madison County, Iowa
Madison County has 11 scored datacenter candidate sites averaging 57.9/100 DC Readiness, with a catalogued aggregate of 2,800 MW. FEMA rates local natural-hazard risk as "Relatively Moderate". The county has a datacenter tax incentive on record.
At a glance
Madison County, Iowa has 11 scored datacenter candidate sites averaging 57.9/100 DC Readiness, roughly in line with the Iowa average of 56.3. It ranks 59th of 85 Iowa counties by number of sites and 24th by average score. The top-scoring site is BOONEVILLE at 66.5/100.
Site-selection context for Madison County
Incentive detail: Sales tax exemption on DC equipment for $1M+ investments; property tax phase-in for new construction.
How does Madison County compare with other counties in Iowa?
By number of scored sites, Madison County ranks 59th of the 85 Iowa counties with a county page, holding 0.4% of the state's 2,572 sites. Its average DC Readiness of 57.9/100 ranks 24th in the state and is roughly in line with the national average of 53.0. Nationally it has the 2327th-largest site inventory of 2,964 counties with five or more sites. 0 sites score 70 or higher and 8 score 55 or higher.
What types of datacenter sites are in Madison County?
Substation-Adjacent sites are the most common (5, 45% of the county's inventory), followed by greenfield (4) and former mine (2). Site type reflects how the parcel was identified — next to a substation, on a former mine or brownfield, on industrial or federal excess land — and is scored on the same 14 factors either way.
What are power cost, hazard, water and fiber conditions in Madison County?
Industrial electricity averages 6.98¢/kWh and commercial 10.61¢/kWh. FEMA's National Risk Index rates the county "Relatively Moderate" (30). WRI water stress is low. 9 fiber providers report service in the county. The climate runs 900 cooling degree days a year with a mean temperature of 48°F. Land is valued around $7,700 an acre.
By site type
Top datacenter sites in Madison County
| Site | Type | Voltage | Capacity | Queue wait | Score |
|---|---|---|---|---|---|
| BOONEVILLE | Substation-Adjacent | 345 kV | 600 MW | 4.3 yrs | 66.5 |
| MADISON COUNTY | Substation-Adjacent | 345 kV | 600 MW | 4.3 yrs | 64.4 |
| Greenfield (UNKNOWN137755 - GRIMES) | Greenfield | 345 kV | 600 MW | 4.3 yrs | 59.5 |
| Greenfield (MADISON COUNTY - BOONEVILLE) | Greenfield | 345 kV | 600 MW | 4.3 yrs | 59.3 |
| EARLHAM | Substation-Adjacent | 161 kV | 100 MW | 4.3 yrs | 59.0 |
| WINTERSET JUNCTION | Substation-Adjacent | 161 kV | 100 MW | 4.3 yrs | 57.7 |
| OZ Madison | Greenfield | — | — | 4.3 yrs | 57.7 |
| UNKNOWN131419 | Substation-Adjacent | 161 kV | 100 MW | 4.3 yrs | 57.1 |
| Greenfield (EARLHAM - BOONEVILLE) | Greenfield | 161 kV | 100 MW | 4.3 yrs | 54.2 |
| Mine Site | Former Mine | — | — | 4.3 yrs | 50.6 |
| Mine Site | Former Mine | — | — | 4.3 yrs | 50.5 |
Every scored site in Madison County
All 11 sites, best first.
- BOONEVILLE · 66.5
- MADISON COUNTY · 64.4
- Greenfield (UNKNOWN137755 - GRIMES) · 59.5
- Greenfield (MADISON COUNTY - BOONEVILLE) · 59.3
- EARLHAM · 59.0
- WINTERSET JUNCTION · 57.7
- OZ Madison · 57.7
- Substation-Adjacent site · 8632fe02 · 57.1
- Greenfield (EARLHAM - BOONEVILLE) · 54.2
- Mine Site · b3bd7250 · 50.6
- Mine Site · 9cb13680 · 50.5
Madison County datacenter FAQ
How many datacenter sites are in Madison County?
11 scored datacenter candidate sites, averaging 57.9/100 DC Readiness. That is the 59th-most of 85 Iowa counties with five or more sites.
What is the highest-scoring datacenter site in Madison County?
BOONEVILLE scores 66.5/100 DC Readiness, the highest of the 11 scored sites in Madison County (a substation-adjacent site).
Does Madison County offer datacenter tax incentives?
Sales tax exemption on DC equipment for $1M+ investments; property tax phase-in for new construction.
What is the natural-hazard risk in Madison County?
FEMA's National Risk Index rates Madison County as "Relatively Moderate" (score 30).
What are industrial electricity rates in Madison County?
Average industrial electricity is 6.98¢/kWh and commercial is 10.61¢/kWh in Madison County.
More in Iowa
- All datacenter sites in Iowa· 2,572 sites
- Operating datacenters in Iowa
- Electric substations in Iowa
- Black Hawk County· 126 sites · avg 58.4
- Pottawattamie County· 123 sites · avg 57.0
- Clinton County· 118 sites · avg 54.2
- Johnson County· 112 sites · avg 57.9
- Linn County· 105 sites · avg 58.3
- Dubuque County· 101 sites · avg 55.8
- Substation-Adjacent sites in Iowa
- Greenfield sites in Iowa
About this data
Source: GridCensus composite of HIFLD transmission and substation data, EIA, FEMA National Risk Index, FCC broadband data, PeeringDB and ISO interconnection queues, as published November 12, 2026 — GridCensus refreshes it monthly. See the methodology for how records are matched, cleaned and scored.
Cite as: GridCensus, “Datacenter candidate sites in Madison County, Iowa”, https://gridcensus.com/datacenter-sites/iowa/madison-county (data as of November 12, 2026).
Dataset updated . Screening estimates derived from public data sources.
Go deeper than the public screen
Every site and score for Madison County, Iowa is free to browse. Pro adds Watchtower on 25 sites, alerts when new candidate sites, datacenters or interconnection-queue requests appear in your markets, score and capacity history, and CSV export. Enterprise adds team seats, weekly data files for all 147,272 sites, the REST API and an MCP server for AI tools.